Fig. 1

Design and experimental timeline of test paradigm for the injected trigger compounds. Following 1 day of habituation (day 0), five tests were done every other day over the course of 9 days. All compounds were injected intraperitoneally (i.p.) except for PACAP38 that was given subcutaneously (s.c.). Anti-PACAP antibodies (30 mg/kg) or IgG control (30 mg/kg) were injected once (day 0) 24 h prior to test day 1. Pre-treatment of sumatriptan (0.6 mg/kg) was given on every test day 20 min prior to the injection of PACAP38. On every test day, the basal threshold of cutaneous sensitivity was measured using Von Frey filaments prior to injections and the acute response after injections was measured after 1 h for PACAP38 and 2 h for GTN and levcromakalim